The phenomenon of the ion-soot interaction in the aircraft plume at the ground conditions is investigated. The ion-soot attachment coefficients, taking into account the polarization of the soot particles in the ion electric field, are calculated. It is shown that the ion-soot attachment may play the important role in the evolution of the ion concentrations in the plume. Comparison of the model results with the ground-based measurements for the ion depletion along the plume demonstrates that the concentration of the positive and negative ions at the nozzle exit for these observations is close to 1.2 x 10(8) cm(-3).